Methods and apparatus for the removal of adsorbable contaminants, in particular, volatile organic compounds ("VOC") from air streams are very well known. Typical of such systems is the use of activated carbon for the removal of VOCs and the use of a heated regeneration gas for desorbing the adsorbed VOCs from the adsorbent. To provide a substantially continuous removal process, at least two adsorber vessels are used in which one adsorber is adsorbing the VOCs from the gas stream while the other adsorber is being regenerated for use. In some cases more than two vessels are used to enhance the continuity of the system's performance.
The apparatus and methods of the prior art that are used for VOC removal from the commercial gas stream provide satisfactory removal rates. However, these processes require the use of large stationary systems with high flow rates of hot desorption (regenerative) gases. Many require the use of external combustion means to heat the desorption gases to facilitate the desorption process, often with inefficient thermal transfer to the adsorbent. These systems also require large processing equipment to handle the large flow of gases to recover or oxidize the solvents/VOCs removed from the adsorbent.
Accordingly, it is an object of the present invention to provide a method and apparatus for the efficient removal of VOCs, other organic contaminates and adsorbable materials from fluid streams using reduced desorbent fluid flows. It is a further object of the invention to provide apparatus for the removal of contaminates which can be made portable and capable of being attached to point sources of contaminate generation. It is yet a further object of the invention to provide an apparatus which is capable of continuous adsorption and removal of VOCs and other adsorbable contaminates with substantially simultaneous regeneration of the adsorbent using reduced flows of desorbent fluids without external heating means to achieve high thermal desorption efficiency.